Can environmental policies improve marine ecological efficiency? Examining China's Ecological Civilization Pilot Zones.

Terrestrial ecosystems can benefit from environmental protection policies; however, their impact on marine ecological efficiency deserves further exploration. This study uses China's Ecological Civilization Pilot Zone (ECZ) policy as an example of a quasi-natural experimental study, with data from 11 coastal provinces in China from 2006 to 2019 as the initial sample. First, a Super-SBM model considers undesired outputs to measure marine eco-efficiency, while a synthetic control method (SCM) investigates the effect of environmental regulations on marine eco-efficiency. The results show that ECZ policies can promote marine eco-efficiency and the effect mechanisms of these policies are discussed from national and regional perspectives. This study contributes to the current literature by theoretically evaluating the impact of ECZ policies on the marine environment in coastal areas, enriching the mechanism of integrated environmental policies on marine ecological protection, and providing references for formulating and implementing environmental policies.